// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_DATABASE_H_
#define CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_DATABASE_H_

#include <memory>
#include <string>

#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/strings/string16.h"
#include "base/strings/string_piece.h"
#include "base/trace_event/memory_dump_provider.h"
#include "content/common/content_export.h"
#include "third_party/leveldatabase/src/include/leveldb/comparator.h"
#include "third_party/leveldatabase/src/include/leveldb/status.h"

namespace leveldb {
class Comparator;
class DB;
class FilterPolicy;
class Env;
class Snapshot;
}

namespace content {

class LevelDBComparator;
class LevelDBDatabase;
class LevelDBIterator;
class LevelDBWriteBatch;

class LevelDBSnapshot {
private:
    friend class LevelDBDatabase;
    friend class LevelDBTransaction;

    explicit LevelDBSnapshot(LevelDBDatabase* db);
    ~LevelDBSnapshot();

    leveldb::DB* db_;
    const leveldb::Snapshot* snapshot_;

    DISALLOW_COPY_AND_ASSIGN(LevelDBSnapshot);
};

class CONTENT_EXPORT LevelDBLock {
public:
    LevelDBLock() { }
    virtual ~LevelDBLock() { }

private:
    DISALLOW_COPY_AND_ASSIGN(LevelDBLock);
};

class CONTENT_EXPORT LevelDBDatabase
    : public base::trace_event::MemoryDumpProvider {
public:
    class ComparatorAdapter : public leveldb::Comparator {
    public:
        explicit ComparatorAdapter(const LevelDBComparator* comparator);

        int Compare(const leveldb::Slice& a,
            const leveldb::Slice& b) const override;

        const char* Name() const override;

        void FindShortestSeparator(std::string* start,
            const leveldb::Slice& limit) const override;
        void FindShortSuccessor(std::string* key) const override;

    private:
        const LevelDBComparator* comparator_;
    };

    static leveldb::Status Open(const base::FilePath& file_name,
        const LevelDBComparator* comparator,
        std::unique_ptr<LevelDBDatabase>* db,
        bool* is_disk_full = 0);
    static std::unique_ptr<LevelDBDatabase> OpenInMemory(
        const LevelDBComparator* comparator);
    static leveldb::Status Destroy(const base::FilePath& file_name);
    static std::unique_ptr<LevelDBLock> LockForTesting(
        const base::FilePath& file_name);
    ~LevelDBDatabase() override;

    leveldb::Status Put(const base::StringPiece& key, std::string* value);
    leveldb::Status Remove(const base::StringPiece& key);
    virtual leveldb::Status Get(const base::StringPiece& key,
        std::string* value,
        bool* found,
        const LevelDBSnapshot* = 0);
    leveldb::Status Write(const LevelDBWriteBatch& write_batch);
    std::unique_ptr<LevelDBIterator> CreateIterator(const LevelDBSnapshot* = 0);
    const LevelDBComparator* Comparator() const;
    void Compact(const base::StringPiece& start, const base::StringPiece& stop);
    void CompactAll();

    // base::trace_event::MemoryDumpProvider implementation.
    bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
        base::trace_event::ProcessMemoryDump* pmd) override;

protected:
    LevelDBDatabase();

private:
    friend class LevelDBSnapshot;

    void CloseDatabase();

    std::unique_ptr<leveldb::Env> env_;
    std::unique_ptr<leveldb::Comparator> comparator_adapter_;
    std::unique_ptr<leveldb::DB> db_;
    std::unique_ptr<const leveldb::FilterPolicy> filter_policy_;
    const LevelDBComparator* comparator_;
    std::string file_name_for_tracing;
};

} // namespace content

#endif // CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_DATABASE_H_
